1. Field of the Invention
This invention relates to the field of telecommunications, and in particular to the design of antenna systems within communication systems.
2. Description of the Prior Art
Communication providers use antenna systems to implement wireless communications. One example of an antenna system provides broadband wireless service. Customers that subscribe to broadband wireless service communicate with a head end. A specific type of broadband wireless system communicates over Multichannel Multipoint Distribution Service (MMDS) frequencies and Multipoint Distribution Service (MDS) frequencies. The MMDS frequencies range from 2500 MHz to 2686 MHz. The MDS frequencies range from 2150 MHz to 2162 MHz. In a typical MMDS system, the bandwidth of the upstream channels is about 6 MHz.
A head end manages the upstream and downstream channels with the customer. The head end also interfaces the customer with communication networks such as the Internet. The head end includes a base antenna comprised of a transmitter antenna and one or more receiver antennas. MMDS requires a line of sight between devices that are communicating. Therefore, the antennas are placed on a high building or a mountain to establish lines of sight with the customers.
The transmitter antenna is omni-directional and broadcasts data from the head end to the customers on the downstream channels. In a two-way wireless system, the receiver antennas are positioned to receive MMDS signals transmitted from customers to the head end on the upstream channels. Each receiver antenna is positioned to receive MMDS signals from customers located within a certain area. The areas formed by the antennas are referred to as sectors. The sectors have designated frequency ranges or designated channels.
With geographic and government regulations, many antenna systems are complex and costly to develop. Some government regulations further increase costs of antenna systems since the antenna systems must also be licensed with respect to power of wireless signals, location of use for the wireless signals, and frequency of the wireless signals. The government regulations provide many challenges when designing and implementing an antenna system. Each new form of antenna system requires a new design and a new implementation. New designs and implementations require new government licenses for power, location, and frequency.
One critical requirement to antenna system design is the decision of the location of the antenna system. The location of the antenna system depends on maximization of customers, geographic constraints, technical constraints, and government regulations. Thus, the decision process of determining the location and configuration of the antenna system is quite complex.
One design system exists which reduces costs associated with antenna system development and government licensing. The design system, called CelPlan® is instrumental is assisting communication providers with development of complex antenna systems. CelPlan® is designed to provide accurate predictions in all commercial frequency ranges for analog, TDMA, and CDMA technologies. However, CelPlan® creates new antenna system designs based on new antenna equipment and locations. Many communication providers have existing equipment that can be modified to work with new antenna systems, but CelPlan® is not capable of using information about existing equipment.